【摘要】 无转速计阶次分析是解决变转速故障诊断问题的有效方法，其关键在于提取时频脊线作为转轴瞬时频率。针对变转速工况下谐波减速器振动信号时频脊线误差大与故障特征阶次提取不准确的问题，提出一种子带平均Hoyer图(subband average Hoyergram, SAH)结合二阶同步提取变换(second order synchroextracting transform, SSET)的变转速谐波减速器故障诊断方法。该方法提出基于双树复小波包变换的SAH,根据最优频段设计带阻滤波器，滤除故障冲击成分所处共振频段；提出SAH-SSET结合快速路径优化算法的时频脊线提取方法，改善频率模糊现象，提取时频脊线进行阶次分析，进而根据包络阶次谱判断谐波减速器故障类型。通过400→1 000 r/min→500 r/min先加速后减速过程的谐波减速器4种故障信号进行试验验证，所提方法时频脊线的均方根误差为0.007 2,极接近于0,决定系数R~2为0.896 0,较对比方法提升0.178 5～0.376 7,更趋近于1,故障特征阶次最大误差为1.19%,较对比方法减少3.63%～4.34%。结果表明，所提方法对变转速下谐波减速器具有良好的故障诊断能力。更多还原

【Abstract】 The tacho-less order analysis is an effective approach for addressing variable-speed fault diagnosis challenges. The key is to extract the time-frequency ridge as the instantaneous frequency of the rotating shaft. Under variable speed conditions, the vibration signal analysis of a harmonic reducer usually meets the problems of large errors of time-frequency ridge and inaccurate extraction of fault characteristics. Aiming at above problems, a fault diagnosis method for harmonic reducers under variable speed was proposed, which combined the subband average Hoyergram(SAH) with the second order synchroextracting transform(SSET). The SAH was constructed based on the double-tree complex wavelet packet transform. Band-stop filter parameters were set according to SAH’s optimal frequency band, and the resonance band containing fault impulse components was filtered out. A time-frequency ridge extraction method integrating SAH-SSET with a fast path optimization algorithm was proposed to reduce frequency ambiguity and extract the time-frequency ridge for order analysis. The fault type of the harmonic reducer was determined according to the envelope order spectrum. The proposed method was verified by using the harmonic reducer’s 4 types of fault signals under the variable speed condition of acceleration first and then deceleration from 400 r/min to 1 000 r/min to 500 r/min. The time-frequency ridge extracted with the proposed method has a root mean square error of 0.007 2 which is extremely close to 0, and presents a coefficient of determination R~2 of 0.896 0, which is closer to 1 and 0.178 5～0.376 7 higher than that of the comparison methods. The maximum error of the fault characteristic order is 1.19%, which is 3.63%～4.34% less than that of the comparison methods. The results show that the proposed method has excellent capabilities of fault diagnosis for harmonic reducers under variable speed.更多还原